Rounding whole numbers example 1 | Arithmetic properties | Pre-Algebra | Khan Academy

TL;DR

Learn how to round numbers to the nearest hundred by identifying the nearest increment of 100 and rounding up or down accordingly.

Transcript

Round 24,259 to the nearest hundred. You're going to find that doing these problems are pretty straightforward, but what I want to do is just think about what it means to round to the nearest hundred. So what I'm going to do is I'm going to draw a number line. Let me draw a number line here, and I'm just going to mark off the hundreds on the number... Read More

Key Insights

• 🫥 Rounding to the nearest hundred can be visualized using a number line, marking off increments of 100.
• 🛝 Identifying the nearest increment of 100 helps determine whether rounding up or down is necessary.
• 💯 Rounding up involves increasing the hundreds place by 1, while rounding down only keeps the digits in the hundreds place.
• 🫥 Drawing a number line is not always necessary, as a more mechanical approach involves looking at the tens place digit.

Questions & Answers

Q: How do you round a number to the nearest hundred?

To round a number to the nearest hundred, look at the digit in the tens place. If it's 5 or greater, round up by increasing the hundreds place by 1 and replacing the digits after it with zeros. If it's less than 5, round down by keeping only the digits in the hundreds place and removing any digits after it.

Q: Why is it called rounding to the nearest hundred?

Rounding to the nearest hundred means rounding to one of the increments of 100 on a number line. It involves finding the nearest increment of 100 and rounding to whichever increment is closest to the given number.

Q: Do you always need to draw a number line to round to the nearest hundred?

No, drawing a number line is one way to understand rounding to the nearest hundred conceptually. However, for more efficient calculation, you can simply look at the hundreds place and round up or down based on the digit in the tens place.

Q: What happens when the tens place digit is exactly 5?

When the tens place digit is exactly 5, you round up according to the rounding rule. This means increasing the hundreds place by 1 and replacing the digits after it with zeros.

Summary & Key Takeaways

• Rounding to the nearest hundred involves identifying the nearest increment of 100 on a number line and determining the exact position of the number.

• In the case of rounding up, if the digit in the tens place is 5 or greater, the number is rounded up by increasing the hundreds place by 1 and replacing the digits after it with zeros.

• When rounding down, if the digit in the tens place is less than 5, the number is rounded down by keeping only the digits in the hundreds place and removing any digits after it.